(75 ILCS 70/1)(from Ch. 81, par. 1201)Sec. 1. (a) The registration and circulation records of a library
are confidential information. No person
shall publish or make any information contained in such records available to the public unless:(1) required to do so under a court order; or(2) the information is requested by a sworn law

enforcement officer who represents that it is impractical to secure a court order as a result of an emergency where the law enforcement officer has probable cause to believe that there is an imminent danger of physical harm. The information requested must be limited to identifying a suspect, witness, or victim of a crime. The information requested without a court order may not include the disclosure of registration or circulation records that would indicate materials borrowed, resources reviewed, or services used at the library. If requested to do so by the library, the requesting law enforcement officer must sign a form acknowledging the receipt of the information. A library providing the information may seek subsequent judicial review to assess compliance with this Section.

This subsection shall not alter any right to challenge the use or dissemination of patron information that is otherwise permitted by law.
(b) This Section does not prevent a library from publishing or making
available to the public reasonable statistical reports regarding library
registration and book circulation where those reports are presented so that
no individual is identified therein.(b-5) Nothing in this Section shall be construed as a privacy violation or a breach of confidentiality if a library provides information to a law enforcement officer under item (2) of subsection (a).
(c) For the purpose of this Section, (i) "library" means any public library
or library of an educational, historical or eleemosynary institution, organization
or society; (ii) "registration records" includes any information a library
requires a person to provide in order for that person to become eligible
to borrow books and other materials and (iii) "circulation records" includes
all information identifying the individual borrowing particular
books or materials.(Source: P.A. 95-40, eff. 1-1-08.)